The present invention concerns a cutter for a square timber hewing machine, consisting of a cutter disk shaped liked a truncated cone and on the mantle surface of which have been affixed cutter bits in consecutive succession in helical configuration so that the cutting takes place with each bit in turn, starting at the outer periphery of the cutter disk and proceeding inward. The cutter bit has one curved cutting edge, or two or more cutting edges located on each other's extension and define an obtuse angle, part of the cutting edge (edges) moving parallel to the wood grain and another part moving obliquely against the grain orientation, the square timber hewing operation being accomplished by feeding the trunk into the interstice of opposing cutters or pairs of cutters.
The object of this invention is to provide a new type of cutter by which several advantages are gained over cutters of prior art.